The present invention relates to an image forming unit and an image forming apparatus.
A conventional image forming apparatus such as a printer, a copier, a fax machine, and a multifunction product thereof is provided with an image forming unit. In the image forming unit, a surface of a photoreceptor drum is charged constantly and evenly, and the surface of the photoreceptor drum is exposed to form an electrostatic latent image thereon. A developing roller develops the electrostatic latent image to form a toner image, and the toner image is transferred to a sheet. Then, the toner image is fixed on the sheet, thereby forming an image.
When the image forming unit forms an image repeatedly, toner as developer is consumed. Accordingly, a toner cartridge as a developer storage unit for retaining toner is disposed separately from a main body of the image forming unit or an image forming unit main body. When an amount of toner becomes low, it is possible to exchange the toner cartridge with a new toner cartridge, thereby replenishing toner.
The toner cartridge is provided with a discharge opening and a shutter at a position corresponding to a supply opening of the image forming unit main body. After the toner cartridge is attached to the image forming unit main body, the shutter is opened or a seal is opened, so that toner is supplied to the image forming unit main body.
In the toner cartridge, a stirring member may be disposed for stabilizing toner thus supplied and stably supplying toner to a developing unit (refer to Patent Reference).
Patent Reference Japanese Patent Publication No. 2004-93924
In a conventional printer, when a discharge opening or a supply opening has a large size, a toner cartridge or an image forming unit main body tends to have low rigidity, or toner may leak to outside. Accordingly, it is difficult to increase a size of the discharge opening or the supply opening.
When a density of toner increases due to vibrations during transportation or own weight, toner in the toner cartridge loses flowability. Accordingly, toner tends to be clogged near the discharge opening or the supply opening, thereby making it difficult to stir toner near the discharge opening. As a result, it is difficult to supply a sufficient amount of toner from the toner cartridge to the image forming unit main body, thereby causing a blurred image and lowering image quality.
In the view of the problems described above, an object of the present invention is to provide an image forming unit and an image forming apparatus capable of solving the problems and supplying a sufficient amount of toner from a toner cartridge to an image forming unit main body, thereby improving image quality.
Further objects and advantages of the invention will be apparent from the following description of the invention.